This invention relates to an improved method for winning bitter substances from hops and rendering them suitable for use as bittering agents in beer making. More particularly, it relates to an improved process for converting the so-called beta-acid component of the hop resins from hop cones, which are normally discarded in conventional brewing processes, into a form which can be used satisfactorily as a bittering agent in beer making. This process is an oxygenation reaction, in which lupulones are converted into hulupones.
Processes for the oxygenation of lupulones to hulupones are described in Belgian Pat. No. 805,280; British Pat. No. 701,177; and U.S. Pat. Nos. 4,013,721; 3,977,953; and 2,652,333.